138 University of California Publications in Zoology 



1-A.. Lacrimal contacts palatine, and prefrontal fails to contact jugal behind lacrimal 

 foramen. 



8-A. Frontal longer than wide. 



9-A. Paired openings near frontonasal suture small or absent. 



10-A. Cristae cranii of frontal form a smooth, continuous curve from frontal to 

 prefrontal. 



1 1-A. Frontal cristae medial to cristae cranii absent or weakly developed. 



12-A. Dorsal borders of orbits form a more or less smooth curve. 



13- A. Parietal foramen lies on frontoparietal suture. 



14- A. Supratemporal extends anteriorly more than halfway across posterior temporal 

 fossa. 



15-A. Lateral surfaces of maxillae relatively flat or concave below supralabial 

 foramina. 



16-A. Premaxillary process of maxilla not curving dorsally; maxillary and premaxillary 

 teeth lie in the same plane. 



17-A. Lacrimal relatively large. 



18-B. Ventral process of squamosal reduced or absent. 



19-A. Squamosal does not abut against tympanic crest of quadrate. 



20-A. Septomaxilla without pronounced longitudinal crest on anterolateral surface. 



2 1-A. Palatine without high crest on dorsomedial surface. 



22-A. Large posterolateral process of palatine behind infraorbital foramen present. 



23-A. Posterolateral process of palatine behind infraorbital foramen fails to contact 

 jugal. Contact of this process with the jugal may be a synapomorphy of all iguanines that 

 has been lost secondarily in Dipsosaurus. 



24-A. Infraorbital foramen located on lateral or posterolateral edge of palatine. 



25-A. Medial borders of pterygoids relatively straight anterior to pterygoid notch, 

 pyriform recess narrows gradually anteriorly. Sharply curved medial pterygoid borders 

 and a pyriform recess that narrows abruptly may be a synapomorphy of all iguanines that 

 has been secondarily lost in Brachylophus. 



26-A. Ectopterygoid fails to contact palatine at posteromedial comer of suborbital 

 fossa. 



27-A. Long parasphenoid rostrum. 



28-A. Cristae ventrolaterals of parabasisphenoid strongly constricted behind 

 basipterygoid processes. 



29-A. Posterolateral processes of parabasisphenoid large, extending far up anterior 

 edges of lateral processes of basioccipital. 



30-A. Laterally directed pointed process of cristae interfenestralis absent. 



3 1-A. Stapes relatively thin. 



32-A. Dorsal edges of dentary and surangular on either side of coronoid eminence 

 approximately equal in height. 



33-A. Splenial relatively large. 



